How to capture error if cron is not running ?

Dear All,
I have a cron job set like this */6 * * * /usr/local/sendClient/runClient.sh>/usr/local/sendClient/cron1.log . The problem I found my cron is not running and I dont know where to get the error why this cron is not running. I have check var/log/cron no error in there too. But when I run my java file which is set to in the runClient.sh it show me the error. How capture the errors? Thank you.

Dear Falko,
Here is my script. Yes manually the script run but now the remote listerning server is down so that is the error which I would like to capture so when I run it manually it can see the error.